Boosting the supercapacitor performances of activated carbon with carbon nanomaterials

Improving the properties of conventional activated carbon electrodes for enhancing the performances of commercial supercapacitors has been an important research topic. Herein, we combine conventional activated carbon and carbon black with carbon nanomaterials (i.e., carbon nanotubes and carbon nanofibers) to develop a new class of nanocomposite electrodes for high-performance supercapacitors. With the synergistic effects from these multiple components, the resultant nanocomposite electrodes exhibit superior performances over conventional activated carbon electrodes. The optimized quaternary nanocomposite electrode shows a high packing density (0.63 g cm−3), a high rate capability (capacitance retains 77.5% at 80 A g−1 vs. 0.5 A g−1), a long cycle life (capacitance retains 91.4% after charging/discharging at 10 A g−1 for 30000 cycles), and high volumetric performances (capacitance: 66.1 F cm−3, energy density: 29.6 W h L−1, power density: 101.7 kW L−1), significantly exceeding those of current supercapacitor technology. The nanocompositing approach developed in the present work can be readily transferred into the industrial slurry process, utilizing commercially available materials, to produce highly capacitive nanocomposite electrodes for manufacturing high-performance supercapacitor products at low costs. Broadly, this approach can be extended for mass-producing high-performance nanocomposite electrodes for other energy-related technologies including, for example, batteries, fuel cells, and solar cells.